Tech: Long lived light bulb

Subject: Tech: Long lived light bulb
From: Tootler
Date: 26 Aug 11 - 02:46 PM

The light bulb in our loft blew last weekend when I was up there. Nothing unusual in that you might say. It was in the loft when we bought the house in 1972 which means that it has lasted almost 30 years. I suspect not a record, but certainly a very long life for a tungsten filament bulb.

It's now been replaced by a cfl; technology marches on.

The light bulb's gone
It was working yesterday
But to day it's gone
The light bulb's gone and blown
I went into the loft and pulled the cord
There was no light, it was dark.

Subject: RE: Tech: Long lived light bulb
From: ClaireBear
Date: 26 Aug 11 - 02:58 PM

Just to add to the merriment, this light bulb has been burning continuously since 1901. Parts of my band were there for its 100th birthday, but we had another gig on its 110th.

Don't miss the BulbCam. Riveting.

C

Subject: RE: Tech: Long lived light bulb
From: Joe Offer
Date: 26 Aug 11 - 04:48 PM

Got a tune for your "Ode On a Light Bulb," Tootler?

;-)

-Joe-

Subject: RE: Tech: Long lived light bulb
From: JohnInKansas
Date: 26 Aug 11 - 07:13 PM

Most standard incandescant bulbs will last at least twice as long as they're designed for if they're run at about 95% of design voltage. It's hard to say how long one might last with some additional reduction in voltage.

The one at the link has a very old filament design (according to the pictures), and possibly was just made with an extra-long filament, effectively increasing the voltage needed to bring it up to a normal bright glow. In the era when it would have been made (and with that kind of filament) it was "hand work" with none of the fancy precision automatic machinery used even a little more recently, so an oddball isn't surprising. Long life in a hundred year old fixture could also be the result of "bad wiring" that reduces the voltage at the bulb. Some wiring newer that that is pretty scary when repairs are needed.

It's not really too surprising that an occasional "misassembled" bulb might last for a very long time, with the old assembly methods, although it's exceedingly unlikely that would be the case with a modern one since quality controls are much more stringent and newer bulbs are exceedingly consistent.

So called "long life" bulbs that sometimes are advertised are just (in most cases) ones with a "long filament" so that they're effectively run at reduced power and filament temperature. The problem with this is that unless brought to full temperature they're very much less efficient, so what you save on bulbs is wasted in increased power consumption if you attempt to get equal light output.

As to the "longer life" of CFL bulbs, I've been using nothing but CFLs for about 12 years now, except in one fixture that used a socket I never found them for. If they're left on almost continuously they do last somewhat longer, although 2x as long is a stretch. If used where they're turned on and off frequently, as in most rooms in a home, about 2/3 as long as a filament bulb is my experience. In my garage, where they're probably exposed to slightly higher ambient temperatures due to a high ceiling and no air conditioning, I'd say they've lasted less than 1/2 as long as the original incandescants that were up there when we moved in. (Three full sets of CFLs replaced in 14 months, turned on perhaps an average of twice per week for a couple of hours.)

The CFL light output is okay for background lighting, but comes nowhere near a properly fixtured incandescant for close work requiring only a little more intensity, and they're total crap for photography if you're at all fussy about color rendition. With fluorescent tubes, you can select from a variety of phosphor combinations to mitigate some of the shortcomings, but so far I haven't seen much real choice in light balance/quality in available CFLs.

I've also tried a few LEDs when they've been advertised as "fantastic improvements," and have yet to find one that I find even tolerable for background lighting. With the popular LED flashlights, I can walk into walls using one, without seeing them; and for trying to avoid wet spots in the grass at night they're a hopeless failure. I'd avoid trying to use one anywhere I can hear moving water, and they're nearly useless even for avoiding a few puddles in the parking lot.

John

Subject: RE: Tech: Long lived light bulb
From: GUEST,999
Date: 26 Aug 11 - 07:29 PM

So many nights, I'd sit by my window,
Waiting for someone to sing me his song.
So many dreams, I kept deep inside me,
Alone in the dark, now you've come along.

And you light up my life,
You give me hope, to carry on.
You light up my days
And fill my nights with song.

Rollin' at sea, adrift on the waters
Could it be finally, I'm turning for home
Finally a chance to say, "Hey, I Love You"
Never again to be all alone.

And you light up my life,
You give me hope, to carry on.
You light up my days
And fill my nights with song.

You, You light up my life
You give me hope to carry on
You light up my days
And fill my nights with song
It can't be wrong, when it feels so right

Cause you, you light up my life

Subject: RE: Tech: Long lived light bulb
From: Joe Offer
Date: 26 Aug 11 - 08:21 PM

No, I know you all want to know this: "You Light Up My life" has both words and music from Joseph Brooks. It won both a Grammy and an Academy Award in 1977. And for that reason, I'm really pissed off that "Singing Through the Hard Times" didn't win a Grammy.

And before you think this gets too far off the subject of light bulbs, remember that the light bulb was an invention, and so was the Gramophone. I knew that Edison invented the light bulb and I assumed the Gramophone was invented by Alexander Graham Bell, but the ever-omniscient Wikipedia says that Edison invented the wax-cylinder phonograph and Emile Berliner invented lateral-cut disc records that he called by the trade name "Gram-o-phone." And Berliner Gramophone had a German division that later morphed into Deutsche Grammophon. But where does the "Gram" come from?

So, now you know more than you ever wanted to know about light bulbs and gramophones.

Oh, and it was Debby Boone, daughter of Pat, who made a hit of "You Light Up My Life." I never liked her, but I thought her dad was kinda cute...

-Joe-

Subject: RE: Tech: Long lived light bulb
From: s&r
Date: 27 Aug 11 - 04:48 AM

Joseph Swan inventor of the light bulb

Stu

Subject: RE: Tech: Long lived light bulb
From: Bonzo3legs
Date: 27 Aug 11 - 05:25 AM

I think we have enough "proper light bulbs" to last 5 years!

Subject: RE: Tech: Long lived light bulb
From: treewind
Date: 27 Aug 11 - 07:50 AM

The 110 year old light bulb was designed as a 60 watt bulb. It's now being run at 4 Watts.

I'd expect any bulb to last a long time if it's run at less than 7% of its design rating.

Subject: RE: Tech: Long lived light bulb
From: Charley Noble
Date: 27 Aug 11 - 10:27 AM

John-

I've had no problem finding "natural light" CFLs at my local Home Depot. We use them (spot light bulbs) all the time for photography and in my mother's art studio. I also find that they seldom last for more than two years.

It is interesting that the ability to make a very long-lasting incandescent bulb was perfected around 1900 but Edison and other electric bulb companies preferred to continue making 1-2 year lasting bulbs. I wonder why?

Charley Noble

Subject: RE: Tech: Long lived light bulb
From: Tootler
Date: 27 Aug 11 - 11:58 AM

We have been using CFLs for some years now and I find that they do last considerably longer than incandescent bulbs; typically 3 - 5 years. We also have regular fluorescent tubes in the kitchen and garage and they last about 5 years at which point I find I usually have to replace both the starter and the tube.

The incandescent bulb in the loft was not used as often as the lights in the rest of the house but, even so, 29+ years is a quite a considerable life for a standard 60W bulb.

Joe,

The "Ode to a light bulb" was sort of based on "The Thrill is Gone". I must try to make up a couple of more verses.

Subject: RE: Tech: Long lived light bulb
From: EBarnacle
Date: 27 Aug 11 - 04:07 PM

Just go direct to LED's. They draw less and will last even longer.

Subject: RE: Tech: Long lived light bulb
From: Bettynh
Date: 27 Aug 11 - 04:27 PM

Wired magazine on the state of lightbulb tech.

Subject: RE: Tech: Long lived light bulb
From: dick greenhaus
Date: 27 Aug 11 - 05:06 PM

Back when incandescent bulbs were the norm, A large company ran a study to try to estimate when bulbs should be changed to minimize failures. They found that the MTBF (mean time before failure) was a direct function of how long the bulb had been in service---the longer they were operated, the longer they could be expected to last.

Subject: RE: Tech: Long lived light bulb
From: Effsee
Date: 27 Aug 11 - 10:13 PM

The biggest reason for a bulb failure is how often it is switched on and off. Mechanical shock, most bulb failures happen on switch on. If it's left on , this doesn't occur.